The present invention relates to a pressure-regulating-type control valve, and particularly to hand-operated pressure-regulating control valves requiring precise and extremely responsive control characteristics.
Typically, pressure-regulating-type control valves employ a control spring, against which a dual-valve assembly is positioned by movement of an operator's handle. In positioning the valve assembly, different degrees of spring compression are obtained. Feedback of the delivery pressure obtained in the open position of the valve assembly is balanced against the spring compression force to lap off the supply of delivery pressure at a value corresponding to the force of compression of the control spring. In counteracting the spring force, however, the delivery pressure is isolated from the portion of the valve assembly to which the operator's handle is connected. Such an arrangement, therefore, leaves the operator insensitive to the effective delivery pressure. That is, the operator has no "feel" of the actual delivery pressure, and thus, has no knowledge of a loss of delivery pressure due, for examaple, to a break in the pressure line or other system failure.